Field of the Invention
The present invention relates to a bag sealing tape, and a banding device and a banding method using the bag sealing tape. In more detail, the present invention relates to a bag sealing tape capable of being repeatedly used without damaging an object that is banded by the bag sealing tape; and the present invention also relates to a banding device and a banding method using the bag sealing tape.
Description of the Background Art
Conventionally, bread, confectioneries, vegetables, fruits, fresh noodles, frozen food, etc., are placed in a to-be-banded object such as a plastic bag and the like, and then an opening of the bag (neck of the bag) is banded with a single-sided pressure sensitive adhesive tape by using a banding device. In such a case, the pressure sensitive adhesive tape is placed on the neck of the to-be-banded object so as to form a ring, and adhesion zones at both ends of the pressure sensitive adhesive tape are stuck together so as to overlap with each other. Therefore, it is difficult to peel off this pressure sensitive adhesive tape when opening the bag, and it is often the case where the bag is torn, or the pressure sensitive adhesive tape or the banded object is cut with scissors to take out contents of the bag. Thus, opening a banded object takes time and effort, and contents remaining in the banded object have to be transferred to another container in to be preserved.
On the other hand, there have been known repeatedly usable resin-made banding materials that has a metal core body (e.g., wire). To band an object, such a resin-made banding material is wound around a neck of a to-be-banded object and both ends of the material are twisted together; and to take out contents, a twisted portion thereof is unraveled to open the banded object. However, it has been inconvenient when disposing of such banding materials, since it is necessary to separate the resin from the wire for proper disposal of different types of materials.
In order to solve such a problem, Patent Literature 1 (Japanese Laid-Open Patent Publication No. 2003-335307) discloses a banding device and a banding structure which can be easily torn when opening a banded object.
However, according to the banding structure disclosed in Patent Literature 1, although the possibility of damaging the bag is reduced, the banding structure cannot be repeatedly used and thereby a sufficient solution is not provided with regard to preservation of contents remaining in the bag.
U.S. Pat. No. 5,389,438 to Miller et al. discloses an adhesive tape in which an adhesive of elastomeric block copolymers and tackifying materials is hot-melt coated onto a flexible backing. The adhesive tape is designed so that two pieces of the tape bonded to each other are shear resistant yet easily peeled apart. In a principle embodiment, Miller et al. teach employing their adhesive tape as patches for closing a disposable diaper. Column 7, lines 7 through 10 of the reference state, “The overlapping portions of the adhesive patches should provide a force to peel generally from 2 to 12 N, preferably from 5 to 7 N.” It will be appreciated that this numerical range is not a value from a tension test performed at a given tension speed, nor is it a value per unit length. On the other hand, a standard test for determining adhesive peel strength is the T-type test (tension test) in which peeling is performed at a tension speed of 300 mm/min, with the T-type peel strength being given as a value per 10 mm.
Under “Testing” in the same column of the patent, Miller et al. explains,                This is run according to PSTC-5 using a polyethylene substrate to which the test tape was applied using a 2-kg hard rubber roller, one pass in each direction at 30 cm/min. An adhesive which has a 90° Peel Value of from 2 to 8 N/25 mm should be useful for making note pads of repositionable sheets like POST-IT™ note pads, because such adhesive-bearing sheets should adhere well to paper and other substrates while being removable without picking fibers, even after prolonged periods of time. When the 90° Peel Value is from 0 to 2 N/25 mm, the adhesive would be most useful in the above-described adhesive-to-adhesive diaper closure as these are the least likely to adhere to ordinary packaging materials or to the non-adhesive surfaces of the diaper and hence will not require the use of a protective tape.        
Hence, Miller et al. discloses a 90° Peel Value of from 2 to 8 N/25 mm (which equals from 0.8 to 3.2 N/10 mm) as a value useful for making note pads of repositionable sheets, such as POST-IT™ pads. The adhesive layers in such note pads are designed for adhering well to paper and other non-adhesive substrate surfaces, however, meaning that they are designed for a purpose different from that of adhesive layers for bag sealing tapes.
And returning to the disposable diaper, Miller et al. discloses a 90° Peel Value of from 0 to 2 N/25 mm as a value most useful for an adhesive-to-adhesive diaper closure. It will be appreciated that this numerical range converted to the per-10-mm length of the T-type peel test is 0 to 0.8 N/10 mm.
U.S. Pat. App. Pub. 2009/0202183 in the name of Hagino discloses film laminate structures for sealable plastic packaging containers. The reference is silent, however, as to technology for bonding an adhesive layer to an adhesive layer; the reference merely discloses technology for forming an adhesive layer having adhesive and non-adhesive portions so that adhesion and peeling-off of the outermost layer (non-adhesive surface) can be carried out repeatedly. That is, Hagino does not teach that the peel strength of an adhesive layer (an adhesive layer to be bonded to an adhesive layer) such as would be employed for a bag sealing tape can be controlled. Nor does Hagino teach the adoption of non-adhesion zones for a bag sealing tape.